Which of the following is the correct plot for the probability density $\psi^{2}(r)$ as a function of distance '$r$' of the electron from the nucleus for $2s$ orbital?

For an electron in the $4f$ orbital,which of the following sets of quantum numbers is correct?

For the energy levels in an atom,which one of the following statements is(are) correct?

Which of the following elements are exceptions to the $(n + l)$ rule?

To which orbital among the following may an electron having zero angular momentum belong?

$(i)$ Write the electronic configurations of the following ions:
$(a)$ $H^{-}$
$(b)$ $Na^{+}$
$(c)$ $O^{2-}$
$(d)$ $F^{-}$
$(ii)$ What are the atomic numbers of elements whose outermost electrons are represented by
$(a)$ $3s^{1}$
$(b)$ $2p^{3}$ and
$(c)$ $3p^{5}$?
$(iii)$ Which atoms are indicated by the following configurations?
$(a)$ $[He] 2s^{1}$
$(b)$ $[Ne] 3s^{2} 3p^{3}$
$(c)$ $[Ar] 4s^{2} 3d^{1}$